I agree that it is not good to top in flower, but it can, and sometimes must be done.

Frankly I don't like the idea of adding any chemical to my plants, will look up Bushmaster and check it out, might have use with some of my taller sativas.

I do not think topping has any effect on the quality of the medicine, I doubt very seriously that the weed is only good for canna butter, actually I could prove it, just not online. Topping will cause many smaller colas on the lower branches that will be larger than usual. By weight, if I do this, I get the same amount of medicine, maybe not the top as big as my arm, but I do not see any quality reduction at all.

I kinda think this is an opinion question that has no perfect answer. I will add, I rarely top an indica at any point, the sativa's I have no choice due to height.